Cooling apparatus for knitting components

ABSTRACT

A needle-selecting actuator ( 5 ) is surrounded by an intermediate ring ( 7 ) at the top, a lower ring ( 9 ) at the bottom, a needle cylinder ( 2 ) inside, and a cover ( 12 ) outside. A cylindrical chamber ( 13 ) is formed between the needle-selecting actuator ( 5 ) and the cover ( 12 ). The cover ( 12 ) is equipped with a ventilator fan ( 17 ) for feeding the air into the cylindrical chamber ( 13 ). The cylindrical chamber ( 13 ) has an opening ( 14, 15; 18 ) through which the air passes. The outside air is fed into the cylindrical chamber ( 13 ) through the means of ventilation/suction ( 17 ), and passes through said opening ( 14, 15; 18 ) to cool the needle cylinder ( 2 ) and its peripheral working components.

FIELD OF THE INVENTION

This invention relates to a cooling apparatus for knitting components(needle cylinder, cam holder, needle-selecting actuator and otherperipheral parts) in a circular knitting machine.

BACKGROUND OF THE INVENTION

When a circular knitting machine is in operation, frictional heat isgenerated between its components. The frictional heat causes thermalexpansion and deformation of the components. Such expansion anddeformation cause damage to knitting tools such as knitting needles andjacks, and brings about abnormalities of the needle selecting apparatus,producing pattern errors. This is a long-standing problem, which hasbecome more serious in recent years. The speed of operation isincreasing, and knitting machines are getting larger and larger,resulting in greater thermal friction. The increase in the use ofelectronic parts has also added to the amount of heat generation.

As a way of solving this problem, a number of methods for cooling thecylinder by air or water were proposed in the past.

For example, JP-A-4-245963 (1992) discloses a cylinder that is providedwith a fluid path through which the air or fluid medium can flow to coolthe cylinder. Forming a fluid path directly on the cylinder, however,entails a high manufacturing cost. It is also suspected that the directcooling effect extends only to the cylinder, leaving the peripheralsinsufficiently cooled.

According to JP-A-6-287844 (1994) by the present applicant, an orificeis provided between the cylinder and the fabric in the lower part of theknitting section of the knitting machine to cool the cylinder and itsperipherals as well as to remove and discharge fiber dust, etc.According to this prior invention, not only the cylinder but also theperipherals are cooled.

According to JP-A-10-60759 (1998), an annular air chamber is establishedbetween the cylinder and the dial, and a pressurized airflow is fed intoit. The invention of this Japanese application was originally intendedto provide an apparatus for preventing airborne cotton or dust, and thecooling of the knitting components per se is not mentioned at all in thespecification. However, as long as an airflow is generated around thecylinder, a cooling effect on the cylinder would be expected. At firstglance, this configuration resembles that of the present invention.Therefore, this prior apparatus will be discussed further in the sectiondescribing the effects of the prior apparatus by way of comparison withthe present invention.

SUMMARY OF THE INVENTION

It is an object of the present invention to produce an apparatus thatexhibits an improved cooling effect on the knitting components as animprovement on the apparatus disclosed in the above-mentionedJP-A-10-60759 (1998).

The cooling apparatus for knitting components in a circular knittingmachine of the present invention is a cooling apparatus for knittingcomponents in a circular knitting machine equipped with a needleselecting actuator for knitting a jacquard fabric. The needle selectingactuator is surrounded by an upper shield at the top, a lower shield atthe bottom, a needle cylinder inside and a cover outside, and acylindrical chamber is formed between the needle selecting actuator andthe cover. The cover is equipped with ventilation means for feeding theair into the cylindrical chamber, and the cylindrical chamber has anopening through which the air passes. In this way, the outside air isfed into the cylindrical chamber by the ventilation means and passesthrough the opening to cool the needle cylinder and its peripheralknitting components.

The opening of the cylindrical chamber is, for example, a gap in theperiphery of the cover. It is preferable to form the upper end of thecover in an inverted L shape orientated towards the other peripheralworking components. The size of the gap in the periphery of the coveris, for example, 5-50 mm.

The opening of the cylindrical chamber can also consist of holes thatpenetrate the upper shield. These holes are preferably slanted so as tobe orientated towards the other peripheral working components. The sizeof each hole is, for example, 5-20 mm, and the number of holes is, forexample, 10-100.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional view of the knitting section of a circularknitting machine according to a first embodiment of the presentinvention.

FIG. 2 is a cross sectional view of the knitting section of a circularknitting machine according to a second embodiment of the presentinvention.

FIG. 3 is a cross sectional view of the knitting section of the circularknitting machine (according to the first embodiment of the presentinvention shown in FIG. 1) showing the points at which temperatures aremeasured for an effect-comparison test.

FIG. 4 is a perspective view of the knitting section of the circularknitting machine according to the first embodiment of the presentinvention shown in FIG. 1.

FIG. 5 shows a modified example of the upper end of the cover for theknitting section of the circular knitting machine according to the firstembodiment of the present invention.

FIG. 6 shows another modified example of the upper end of the cover forthe knitting section of the circular knitting machine according to thefirst embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will now be described by referenceto the accompanying drawings.

FIG. 1 is a cross sectional view of the knitting section of a circularknitting machine according to the first embodiment of the presentinvention. The knitting section is established above a bed 1 which issupported by a number of legs (not shown). The main components of theknitting section are the cylinder needle part, the yarn carrier part,the actuator part and the knitting needle controlling cam part.

In the cylinder needle part, a cylinder needle (not shown) is disposedin such a way that it is vertically slidable along a needle groove (notshown) formed on the periphery of a rotary needle cylinder 2. The rotaryneedle cylinder 2 rotates at the same speed as a gear ring 3 which ispositioned beneath the needle cylinder 2. In the yarn carrier part, ayarn carrier 4 feeds yarn to the knitting needle. In the actuator part5, needles are selected in such a way as to give variety to the knitfabric. In the cylinder needle controlling cam part, a cam (not shown)housed in a cylinder cam holder 6 imparts a vertically reciprocalmovement to the cylinder needle.

The cylinder cam holder 6 is supported by an annular intermediate ring7, and the intermediate ring is further supported by the bed 1 via asupport 8. The actuator 5 is established on a lower ring 9 which isfastened to the bed.

The machine shown in FIG. 1 is a double-knit circular knitting machine,which also has a dial needle part and a dial needle controlling campart. In the dial needle part, a dial needle (not shown) is disposed insuch a way that it is horizontally slidable along a needle groove formedon the upper surface of a needle dial 10. In the dial needle controllingcam part, a cam (not shown) housed in a dial cam holder 11 imparts ahorizontally reciprocal movement to the dial needle.

On the peripheral side of the space between the intermediate ring 7 andthe lower ring 9, a cylindrical cover 12 is mounted. This cover 12 formsa cylindrical chamber 13 which is enclosed by the intermediate ring 7 atthe top, the lower ring 9 at the bottom, and the actuator 5 and thecover 12 at the sides.

The lower end of the cover 12 makes contact with the lower ring 9, whilethe upper end is positioned slightly above the upper surface of theintermediate ring 7. The top portion 12 a of cover 12 has an inverted Lshape in cross-section. Between this inverted L shaped top portion 12aand the upper surface of the intermediate ring, there is established anopening 14 that opens to the cylinder cam holder 6, while a gap 15 isalso established between the periphery of the intermediate ring and thecover 12 so that the air flow is not obstructed. The size of the opening14 and the gap 15 is preferably 5 to 30 mm, more preferably 10-20 mm,and most preferably about 15 mm.

Because the purpose of the cover 12 is to form an air-flow passage, itcould be made of any material, but from the standpoints of ease ofmanufacture, weight and cost, synthetic resin is preferable. Suchsynthetic resin could be transparent or colored. The synthetic resin,however, must have the strength to endure the passage of the air flow aswell as the load of a ventilator fan described below.

As shown in FIG. 4, the cover is usually a unit consisting of from twoto six elements, and each element is provided with an opening 16 forhousing a support and another opening (blocked by a fan and not visiblein FIG. 4) for housing the ventilator fan described below. The two tosix cover elements could be completely joined with each other with theirend surfaces in contact with each other, but for the ease of repair orreplacement of the actuator or cleaning of the cylindrical chamber, theend surfaces of the cover elements are preferably positioned slightlydisaligned from each other inward or outward, and a rail is provided atthe lower end of the cover so that the cover elements can slide.

In order to feed the outside air into the cylindrical chamber 13 throughthe opening on the side wall of the cover, at least one ventilator fan17 is attached thereto.

For the ventilator fan 17, a propeller fan, for example, by OrientalMotor K.K., Taiko-ku, Tokyo, (model number: MU1238A-11B) can be used.The number of fans can vary according to the size of the circularknitting machine, but for a circular knitting machine of a diameter of30 inches, from 1 to 10, preferably from 3 to 8 and most preferably 5 or6 fans are used. Each ventilator fan 17 is preferably provided with afilter (not shown) at the suction inlet of the fan.

According to this configuration, as indicated by the arrows in FIG. 1,the outside air is drawn into the cylindrical chamber 13 by theventilator fan 17, and runs through the gap 15 and the opening 14, andupwards along the cylinder cam holder 6, cooling the parts along theway.

FIGS. 5 and 6 show two modified forms of the inverted L-shaped cover top12 a. In the modified form shown in FIG. 5, the tip of the cover isprovided with a shutter 20 that closes or opens the opening 14 via ahinge 22. The hinge 22 can be made of any material as long as it islight enough to be opened or closed by air pressure. While the knittingmachine is in operation, the shutter 20 is lifted upwards by the airrunning towards the core knitting section, so it does not block the airpassage. On the other hand, when the knitting machine is out ofoperation for the purpose of cleaning the knitting machine using an airgun 19, the opening 14 is closed by the weight of the shutter 20 itselfand the pressure of the air, thus preventing the intrusion of cottondust.

In the modified form shown in FIG. 6, a filter 21 covering the entirearea of the opening 14 is established at the tip of the cover top 12 a.The filter can be made, for example, of a net equipped with meshes of asize capable of preventing the intrusion of cotton dust. While theknitting machine is in operation, the air running towards the coreknitting section passes the net freely, so the net does not block theair passage. On the other hand, when the knitting machine is out ofoperation for the purpose of cleaning the knitting machine using the airgun 19, the filter prevents the intrusion of cotton dust.

FIG. 2 is a cross sectional view of the knitting section of a knittingmachine according to the second embodiment of the present invention. Theparts that are functionally equivalent to those used in the firstembodiment are given the same numbers, and their detailed explanationsare not repeated.

The second embodiment is different from the first embodiment in respectof the following points:

1. The cover 12 is mounted so as to almost completely seal the spacebetween the intermediate ring 7 and the lower ring 9.

2. Air holes (openings) 18 are formed so as to penetrate theintermediate ring 7 as well as a cylinder-cam-holder mount 6 a which isused to mount the cylinder cam holder 6 onto the intermediate ring 7.

The number of air holes 18 can vary according to the size of thecircular knitting machine, but for a circular knitting machine of adiameter of 30 inches, such number can be 10-100, but is preferably30-80 and most preferably 50-60. The size of each air hole is preferably5-20 mm, more preferably 8-15 mm and most preferably about 10 mm.

EFFECTS OF THE INVENTION

Using a double-knit circular knitting machine equipped with aknitting-tool-controlling apparatus (JP-A-9-21042 (1997)) by the presentapplicant, the temperatures of various parts of the knitting sectionwere measured in order to compare operating results where the knittingmachine is equipped with the apparatus of the present invention withoperating results where the knitting machine is not equipped therewith.

The common knitting conditions were as follows:

Diameter of the knitting machine: 30 inches

Rotational frequency of the knitting machine: 23 rpm

Knit fabric: Interlock

Yarn: Polyester 75 denier

The different knitting conditions were as follows:

Prior Art 1

A sealed-type cover was installed. Because no ventilator fan wasinstalled, there was no air flow into the inside of the cover. When themachine was run approximately 6,000 cycles under the above conditions,the temperature measurement exceeded 80° C., when the measurement wasstopped.

Prior Art 2

A sealed-type cover and a fan were installed. This configuration issimilar to JP-A-10-60759 (1998) referred to in the description of theprior art. In this configuration, the machine was run 10,000 cycles, andtemperatures were taken when they stabilized.

The Present Invention

In the configuration described in the first embodiment (i.e., the sizeof the opening and gap were 15 mm each, and the number of fans was 6),the machine was run 10,000 cycles, and temperatures were taken when theystabilized.

Results

The results are shown in Table 1 below.

TABLE 1 Unit: ° C. Prior Art 1 Prior Art 2 First Embodiment (6) Cylindercam holder 76 73 59 (7) Intermediate ring 58 49 48 (5) Actuator 83 51 50(13) Inside cover (cylindrical 63 34 41 chamber) (2) Needle cylinder 89— 60 Room temperature (3 m away 23 20 26 from the knitting machine)

Observation

The reason that the needle cylinder measured the highest temperatures isthat when the knitting machine runs at high speed, friction occursbetween the knitting tools (knitting needles, jacks, etc.) and theneedle cylinder. Using the apparatus of the first embodiment of thepresent invention lowered the temperature (of the needle cylinder) whencompared to Prior Art 1 by 29° C. The cylinder temperature of Prior Art2 was not measured.

In Prior Art 1, the actuator generated the second highest temperature.The reason is that when knitting an interlock knit fabric as used inthis test, the power consumption of the actuator is fairly large. Usingthe apparatus of the first embodiment of this invention, however,lowered the temperature of the actuator by 33° C. compared with PriorArt 1. Prior Art 2 resulted in a temperature 32° C. lower compared withPrior Art 1.

Heat from the intermediate ring is caused by thermal conduction fromother parts as well as by the friction with the cams, etc., that arefastened to the intermediate ring. Using the apparatus of the firstembodiment lowered the temperature of this part by 10° C. compared withPrior Art 1. Prior Art 2 resulted in a temperature 9° C. lower comparedwith Prior Art 1.

Except for the needle cylinder, for which the temperature was notmeasured for Prior Art 2, the present invention and Prior Art 2 did notproduce significant differences in respect of the temperatures of theactuators and of the intermediate rings. The difference between thepresent invention and the prior arts was most significant in the case ofthe cylinder cam holder.

Heat from the cylinder cam holder is caused by the heat generated by theneedle cylinder as well as by the friction with the cylinder cams, etc.,that are fastened to the cylinder cam holder. While the apparatus of thefirst embodiment lowered the temperature of this section by 17° C.,Prior Art 2 only lowered it by 3° C.

The temperature inside the cover of Prior Art 2 (34° C.) is lower thanthat of the first embodiment of the present invention (41° C.) by 7° C.It is believed that because the air of the test room was fed into thechamber inside the cover using a fan, the difference in the roomtemperatures in the case of the first embodiment (26° C.) and in thecase of Prior Art 2 (20° C.) was directly reflected in the temperaturesinside the cover. The difference between the room temperature and thetemperature of the air inside the cover is about the same in each ofthese cases.

According to the above observation, the present invention is capable ofefficiently cooling the needle cylinder and its peripheral parts using arelatively simple configuration. Even when compared with the closestprior art, the present invention produces an excellent result in respectof the cooling of the needle cam holder.

As a supplemental advantage of the present invention, the air flowingout of the opening is effective in blowing away the lint floating in theknitting section, thereby reducing its adherence to the knitting yarnand the resulting occurrences of defective fabrics and lowering of theoperation rate of the knitting machine.

That which is claimed:
 1. A cooling apparatus for working components ina circular knitting machine having a needle selecting actuator (5) forknitting a jacquard fabric; said needle-selecting actuator (5) beingsurrounded by an upper shield (7) at the top, a lower shield (9) at thebottom, a needle cylinder (2) inside, and a cover (12) outside, acylindrical chamber (13) being formed between said needle selectingactuator (5) and the cover (12); said cover being equipped with a meansof ventilation/suction (17) for feeding the air into the cylindricalchamber (13); said cylindrical chamber (13) having an opening (14, 15;18) through which the air passes; whereby outside air is fed into thecylindrical chamber (13) through the means of ventilation/suction (17)and passes through said opening (14, 15; 18) to cool the needle cylinder(2) and its peripheral working components.
 2. An apparatus according toclaim 1, in which said opening of the cylindrical chamber is a gap (14,15) in the periphery of the cover.
 3. An apparatus according to claim 2,wherein the upper end (12 a) of the cover is formed in an inverted Lshape orientated towards the other peripheral working components.
 4. Anapparatus according to claim 2, wherein the size of the gap (14, 15) inthe periphery of the cover is 5-30 mm.
 5. An apparatus according toclaim 1, wherein the opening (14) is provided with a freely openable andclosable shutter (20).
 6. An apparatus according to claim 1, wherein theopening (14) is provided with a filter (21).
 7. An apparatus accordingto claim 1, wherein the opening of the cylindrical chamber comprises airholes (18) that penetrate the upper shield.
 8. An apparatus according toclaim 7, wherein said air holes (18) are slanted so as to be orientatedtowards the other peripheral knitting components.
 9. An apparatusaccording to claim 7, wherein the size of each air hole is 5-20 mm. 10.An apparatus according to claim 7, wherein the number of said air holesis within the range of 10-100.